Electric power lines can be used to access external (backbone) communication networks, such as the Internet. For example, EP patent publication 0 975 097, the disclosure of which is incorporated herein by reference, describes a method of exchanging data between a customer and a service provider over low and medium voltage AC electric power networks.
In forming electrical access power connections, similar to asynchronous digital subscriber line (ADSL) connections, each user is provided with a home electrical power modem for connection to the power lines within the user's home or office. In addition, a service provider locates an access modem on the electric power lines at a connection point to the external network, near the user's home. Some service providers connect more than one home electrical power modem to a single access modem in order to reduce the number of access modems required. The maximal distance between the home modems and the access modem is, however, limited, due to the relatively high level of noise on electrical power lines.